Recently, plural communications satellites have been launched to locations spaced by a small distance on the same orbit. In order to receive electromagnetic waves from such closely spaced satellites, an antenna with one reflector and plural horns would be used. An example of such antennas is disclosed in JP 2002-124820 A.
According to JP 2002-124820 A, a multibeam primary radiator apparatus is disposed near the focal point of the reflector. The multibeam primary radiator apparatus includes two waveguides disposed in parallel with each other, and the horns are mounted at the distal ends of the respective waveguides. Each of the horns has circular apertures at its distal and proximal ends, respectively.
The antenna disclosed in JP 2002-124820 A can receive electromagnetic waves from two closely spaced communications satellites. In recent years, there are cases in which two communications satellites are launched to locations more close to each other than ever, for example, spaced by an angular distance of 1.9 degrees. It is difficult to closely dispose horns with circular apertures at their distal and proximal ends, in order to receive waves from such further closely spaced communications satellites.
An object of the present invention is to provide a multibeam primary radiator apparatus which can receive electromagnetic waves from closely spaced geostationary satellites. Another object of the invention is to provide a feed apparatus with such multibeam primary radiator apparatus and a multibeam antenna with such feed apparatus or the multibeam primary radiator apparatus.